Scattering of phonon by stacking faults and dislocation cores in plastically deformed LiF crystal: An analysis

Abstract

The present work studies and analyses the effect of compression on LiF crystal. The compression is of the order that it deforms the LiF crystal plastically. The sequence of closed packed structure of plastically deformed crystal is disturbed and we expect stacking faults i.e., faults in the crystal along a plane. Plastically deformed crystal contains high density of dislocations. The depression of phonon conductivity in plastically deformed crystal is associated with interaction of the phonon with high density of dislocations. Phonon or the quantised lattice wave scatters with these stacking faults and dislocation cores, as a result, there is depression of lattice thermal conductivity near the peak. The number of stacking faults/cm N[Formula: see text] has been calculated which is of the order of 101/cm, and dislocation core size which is of the order of burger vector if dislocation density is of the order of 108/cm2. Separate contributions of relaxation rates for various phonon scattering processes have been calculated for both longitudinal and transverse phonons. Present work strongly supports that phonons are mainly scattered by stacking faults and dislocation cores in plastically deformed LiF crystal.